Tag Archives: mpls

MPLSs’ original goal was to increase the routers’ packet processing speed. But now, due to advancement in ASIC, it is primarily used for traffic engineering. Terminologies: LSP – Label switched path. A unidirectional logical link created by MPLS protocol. LSR … Continue reading →

There are some timers associated with LDP. The LDP process consist of LDP discovery by which an LDP adjecency will be formed and LDP session (TCP). Note; if there are more than one links between 2 LSRs, there will be … Continue reading →

Below are some important MPLS-TE notes; MPLS TE- Traffic Engineering In an IP network, routing based only on Destination address. Result in one link being over utilized and another link to under-utilized. We can never do load balancing equally with … Continue reading →

R0(config-if)#tunnel mpls traffic-eng autoroute announce This command is to make the head-end LSR to insert IP destinations into the routing table with tunnel interface as next-hop or outgoing interface. <Before this command applied>

For MPLS-TE, there are two steps. One: create a tunnel between head end LSR and tail end LSR. Second: Forward traffic via tunnel which now act as virtual link. Here, configuration for tunnel creation is described. Steps to enable MPLS-TE:

When CE-PE protocol is OSPF, we use “down bit” and “domain tag” to prevent routing loop to occur. When CE-PE protocol is ISIS, we use “up/down” bit for loop prevention. This bit is the higher order bit in the default … Continue reading →